The present invention relates to a variable-trim frame for two-wheeled vehicles, in particular for mountain bikes.
It is known that the inclination of the steering tube of the front wheel of a two-wheeled vehicle significantly influences the stability of the vehicle itself. In particular, in a case where the vehicle, for example a bicycle, is about to begin a sharp downhill run, a greater inclination of the axis, as denoted by reference numeral ϕ2 in FIG. 1B, enables better control of the means, reducing the risk of tipping over during a steering and braking step. Vice versa, during movement on a flat terrain, an accentuated inclination of the above-mentioned axis is disadvantageous, because it forces the user into a less comfortable position, and makes use of the handlebar more troublesome, as a trim with a less inclined axis is advantageous, as denoted by reference numeral ϕ1 in FIG. 1A.
Therefore, the market has a need for a frame for two-wheeled vehicles which enables a user to simply and rapidly vary the angle of inclination of the steering tube of the front wheel to suit the features of the trajectory to be undertaken. In particular, this need is felt in a case of bicycles of the mountain bike type, often used for arduous routes where there are frequent changes of inclination.